Construction panel with improved locking mechanism allowing for separable connection with like building panels

ABSTRACT

A panel-shaped, rectangular construction panel that includes: a visible face; a base face located opposite to the visible face; two first shaped side faces that run parallel to each other, and two other, second shaped side faces, also parallel to each other, that run perpendicular to said side faces, wherein all of the side faces are bordered by the visible face and the base face; and at least one pair of locking mechanisms that are incorporated in the side faces of the construction panel, are compatible with each other and, when assembled, work together to allow for a separable connection between like construction panels.

BACKGROUND

Embodiments of the present invention relate to a construction panel in the form of a rectangular panel, comprising:

-   -   a visible face;     -   a base face located opposite to the visible face;     -   two first shaped side faces that run parallel to each other, and         two other, second shaped side faces, also parallel to each         other, that run perpendicular to said side faces, wherein all of         the side faces are bordered by the visible face and the base         face;     -   at least one pair of locking mechanisms that are incorporated in         the side faces of the construction panel, are compatible with         each other and, when assembled, work together to allow for a         separable connection between like construction panels, wherein         the locking mechanisms located on the side faces of the         construction panel create a positive groove and tongue         connection when connected to a like construction panel,         -   in which the locking mechanism comprises a trapezoidal             groove that tapers in the direction of the groove bottom             thereof and has a first groove flank that runs substantially             parallel to the visible face, and a second, inclined groove             flank located opposite to the first groove flank, wherein             the second groove flank transitions over a rounded step into             a sunken depression with respect to the groove, which is             located outside of the locking mechanism, said depression             being arranged on a side piece that protrudes beyond the             groove and tapers into a lip, the lip being bordered by a             planar inner wall and a free surface that is plane-parallel             to the base face,         -   and in which the locking mechanism also comprises a             trapezoidal tongue that engages in the groove and             additionally transitions into an approximately semicircular             projection that is oriented toward the base face and will be             accommodated in the depression, wherein the semicircular             projection adjoins a recess in which the lip engages.

A construction panel, and more specifically a floor panel, of the type described above is known from Applicant's EP 1585876 B1. These floor panels, engineered according to the state of the art, have performed reliably in the marketplace and continue to be sold. The structure of these known floor panels ensures unimpeded sliding when dimensional changes occur perpendicular to the long side of the floor panel, as the result of moisture.

There is a need, however, to further develop the construction panels, particularly with respect to their ability to slide against each other along the long sides thereof, and to reduce internal stress in the regions where the construction panels connect.

BRIEF SUMMARY

According to this invention, the problem is solved by a generic construction panel, in which:

-   -   the inner wall of the lip extends, on one hand, to a rounded         glide surface facing a depression and adjoining the free surface         of the lip and, on the other hand, to a depression edge located         in a lowermost region of the depression near the base face, so         that the depression, starting from the depression edge thereof,         rises steadily toward the rounded step; and     -   after the tongue has been inserted into the groove, the         projection is accommodated in the depression in such a way that         a clearance approaching a zero value is created between the         projection and a transition from the inner wall to the glide         surface, or a linear contact is formed.

Hereafter, the term “construction panel” may be replaced by the term “floor panel,” which, however, also refers to wall or ceiling coverings, or to furniture panels. A floor panel is defined here as an object in the shape of a panel characterized by a long side and a short side. The term “rounded glide surface” can refer to a cylindrical glide surface, as well as to divergent geometrical shapes, such as parabolic or elliptical shapes.

The floor panels according to this invention can be made of wood, wood-based materials, plastic or metal, and may be of a solid, i.e., single-layer, or multi-layer design. In addition, the floor panels may be made of solid wood or so-called HDF laminate (high density fiberboard) or of MDF laminate (medium density fiberboard), or of other wood-based materials, including combinations of wood composites and plastic.

The invention particularly relates to embodiments in wood. Wood floors are generally durable and hold up well under pressure. An important feature of wood floors is their tendency to absorb and release moisture, and consequently to expand and shrink. Wood or wooden materials offer many positive characteristics, such as air ionization, micro-climate regulation of interior rooms, and protection against electrostatic charges and dust attraction. Their anti-allergic effects are also well-known.

The inner wall of the lip can be arranged perpendicular or obliquely to the base face. However, an oblique arrangement of the inner wall is preferred, wherein the inner wall is at an acute angle to a plane that is perpendicular to the base face, or at an obtuse angle (complementary angle) thereto.

The step that is opposite to the inner wall and leads to the depression can be situated within or outside of a projection of the side groove on the base face.

In principle, there is negligible clearance between the projection and the transition from the inner wall to the glide surface when the floor panels are made of single-layer solid wood. This is due to the wood fibers in the floor panel that run substantially in a longitudinal direction and are subject to the greatest degree of expansion when exposed to moisture. The clearance can have a value between 0.01 mm and 0.20 mm, and a value between 0.12 mm and 0.15, with a panel thickness of 14 mm, is preferred.

Conversely, in multi-layer floor panels (triple layers, in the present case), there is a linear contact, rather than a clearance, since the dimensional increase is not equal, but different for all three layers. The total dimensional increase resulting from changes in volume caused by moisture or temperature is smaller than that in the case of floor panels made of solid wood. In this connection, reference is made to Applicant's previous documents EP 1585876 B1 and DE 203 21 445 U1, and the full scope of the disclosure thereof is to be incorporated in the present invention.

As a rule, the wood fibers of the upper and lower layers (usage layer and bottom layer) run parallel to the long side of the floor panel, while those in the middle layer (core layer) run perpendicular to the long side of the floor panel. As a result, expansion of the upper and lower layers occurs perpendicular to the long side, both in-plane with the panel and perpendicular to the panel surface.

The expansion of the core layer occurs perpendicular to the long side, but in a plane that is perpendicular to the base face and parallel to the long side in the panel plane. The latter expansion direction has no practical bearing on dimensional changes to the panel connection. The longitudinal arrangement of the fibers in the core layer, which is opposed to the expansion direction of the usage and bottom layers, effectively overcomes the expansion force of these two layers.

The shape of the cross section of the lip is chosen in such a way that the height dimension of the lip, measured from the base face, approximately corresponds to a height where a transition from the step to the groove flank is situated.

The depression can be level and/or bow-shaped. The depression is preferably divided into two regions in the form of circle-sections. The region closer to the inner wall has a radius that is equal to a radius of the glide surface. The remaining region of the depression has a radius that exceeds the value of the other radii.

It is particularly advantageous that the contact surface of the projection with the depression or the point of transition from the inner wall to the glide surface is limited to the aforementioned linear contact. This significantly improves the slide of the floor panels with respect to each other, both during and after installation.

An advantage is that the normally occurring stresses, at least on the long sides of the new panel construction, as well as any potential concavities in the usage layer in the region of the abutting surfaces can be avoided or considerably limited.

Possible woods for the floor panel according to this invention include, among others, the following domestic types of wood, as well as especially hardy tropical varieties:

-   -   American maple     -   American black cherry     -   American walnut     -   Bamboo, light     -   Birch     -   Pear     -   Bubinga     -   Beech     -   Cabreuva     -   Cumaru     -   Diamond wood (Guatambu)     -   Doussie (afzelia superior)     -   Oak     -   Alder     -   Ash     -   Eucalyptus     -   European maple (mountain maple)     -   European cherry     -   Hevea     -   Ipe     -   Iroko     -   Jatoba     -   Kempas     -   Mahogany     -   Merbau     -   Mutenye     -   Niangon     -   Padouk     -   Rosewood     -   Peroba     -   Pitch pine     -   Red pine     -   Sucupira     -   Tali-Missanda     -   Teak     -   Tigerwood     -   Wenge (Panga-Panga)

Woods from responsible and sustainable lumber operations are stamped with the FSC (Forest Stewardship Council) seal and are preferred for production.

The Brinell hardness of the wood varieties listed above is between 43 N/mm² (mountain maple) and 90 N/mm² (Sucupir).

The invention also relates to a surface covering consisting of trimmed construction panels of the type described above. The surface covering can be a floor, wall or ceiling covering, facade siding, or furniture paneling.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings describe exemplary embodiments of the invention in greater detail. The drawings and the particulars of the figures include important information that will be appreciated to those skilled in the art in contemplating the figures. The figures show:

FIG. 1 a floor panel according to the invention in a top view of the flat face;

FIG. 2 section A-A from FIG. 1;

FIG. 3 a section of an enlarged detail of the side face with a groove, which extends along the long side, and is shown in FIG. 2;

FIG. 4 a section of an enlarged detail of two floor panels having multiple layers in the vicinity of the longitudinal side faces thereof after assembly;

FIGS. 5 to 7 sections of an enlarged detail of another variant of the side face, with the groove shown in FIG. 3, with the step to the depression set back;

FIG. 8 a a section of an enlarged detail of two floor panels having multiple layers, after assembly;

FIG. 8 b a section of an enlarged detail of two solid floor panels, after assembly;

FIG. 9 section B-B from FIG. 1;

FIGS. 10 and 11 sections of enlarged details of two floor panels having multiple layers in the vicinity of the narrow sides thereof, before and after assembly;

FIG. 12 a perspective view of the floor panels shown in FIG. 11 during assembly.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.

Although the following text sets forth a detailed description of at least one embodiment or implementation, it is to be understood that the legal scope of protection of this application is defined by the words of the claims set forth at the end of this disclosure. The detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments and/or implementations are both contemplated and possible , using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims

To allow for better understanding of the exemplary embodiments, the following concepts, used in connection with the drawings, will be explained:

-   -   The “visible face,” which is also called the tread surface,         constitutes the top of the floor panels, after installation,         i.e., the usage layer thereof;     -   The “base face” corresponds to the underside of the floor panel         that is opposite the visible face;     -   “Abutting surface,” or “abutting” refers in this case to two         surfaces of the side faces, particularly in the usage layer,         which are oriented perpendicular to the visible face or base         face, and are in contact with each other;     -   “Counter panel” refers to a floor panel that works together with         the counterpart thereof and is of the same design. In the         present case, the counter panels are indicated by the reference         symbols 100′, 200′, and 300′;     -   “Side face” means the floor panel face that borders the visible         and base faces and extends from the edges thereof;

Terms such as “above,” “upper,” “below,” “lower,” “lowermost,” “under,” “over,” left,” “right,” etc. refer to the floor panels installed on a horizontal bottom surface as shown in the drawing.

FIG. 1 shows a rectangular floor panel 100, 100′, or 200, 200′, in a schematic top view of the visible face 11 thereof. The floor panel 100, 100′ or, 200, 200′, has two side faces 1.1, 2.1 that are parallel to each other, and two side faces 1.2, 2.2 that are perpendicular to the side faces 1.1, 2.1, with the side faces 1.1, 2.1 being arranged on the long sides and the remaining side faces 1.2, 2.2 being arranged on the short sides of the floor panel.

Given the schematic representation in FIG. 1, the details of the side faces 1.2, 2.2; 1.2, 2.2 cannot be seen. These will be covered in the present description by way of additional figures. FIG. 1 shows two different embodiments of the floor panels. The differences between the embodiments relate only to the long sides of the floor panels.

The floor panel 100, 100′ is shown in greater detail in FIGS. 2, 3, and 4. The side faces 1.1, 2.1 along the long sides have locking mechanisms 9; 19, which form a tongue and groove connection 40 as shown in FIG. 4.

According to FIG. 2, the floor panel 100, 100′ consists of three layers, namely a bottom layer 7, an upper usage layer 5 having a visible face 11, and a central core layer 3. FIG. 2 further schematically depicts expansion directions QR1, QR2, QR3, and QR4.

The wood fibers of the usage and bottom layers 5; 7 run parallel to the long side of the floor panel (not visible in FIG. 2). The expansion direction QR1 is indicated by arrows pointing perpendicular to the long side. The expansion direction QR2 is indicated by arrows pointing perpendicular to the visible face or the base face.

In the core layer 3, a schematic view of wood fibers 23 that run perpendicular to the long side is shown. QR3 indicates an expansion direction perpendicular to the long side and to the base face 12. The obliquely extending expansion direction QR4 is indicated by oblique arrows. The expansion direction QR4 corresponds to the direction of the long side; thus it is also parallel to the panel plane, shown in FIG. 2 as point P.

The side face 2.1 comprises, starting from the visible face 11, an abutting surface 28.1, a groove 13, and a lower side piece 4, which protrudes beyond the abutting surface 28.1 and ends with an upwardly oriented lip 8.

The side piece 4 has a depression 10 that, on one hand, adjoins an inner wall 21 of the lip 8 and, on the other hand, adjoins a gently rounded step 17, which in turn transitions into a lower, oblique groove flank 25 of the groove 13. A free, upper surface 44 of the lip 8 transitions along a rounded glide surface 20 into the inner wall 21. An upper, second groove flank 15 of the groove 13 is parallel to the visible face 11. The groove 13 is thus shaped as an orthogonal trapezoid, and thus tapers towards the groove bottom 14 thereof.

The locking mechanism 19 comprises a trapezoidal tongue 24 that protrudes beyond an abutting surface 28.2 and then continues in a semicircular, downwardly oriented projection 26. In the assembled state according to FIG. 4, the projection 26 is located slightly above the depression 10, so as to form a clearance 29 there. The projection 26 is, however, supported on a transition 18 from the inner wall 21 to the glide surface 20, in such a way as to create a linear contact 41 which can be seen as a point in FIG. 4.

The abutting surface 28.1 (see FIG. 3) ends with a lower bevel 45 in the region of the usage layer 5. The bevel 45 leads to a rounding 46 that in turn adjoins the upper groove flank 15.

FIG. 5 shows a floor panel 200, or 200′, in the region of the side face 2.1 thereof, which differs from the first embodiment according to FIG. 3 in terms of the manner in which the transition 17 is arranged. The transition 17 is located in front of a plane E1 that is defined as a downward continuation of the abutting surface 28.1. FIG. 5 also shows that the inner wall 21 is arranged obliquely with respect to the base face 12.

As shown in FIG. 6, the inner wall 21 assumes an acute angle β with respect to a plane E2 that is defined by the transition 18 from the glide surface 20 to the inner wall 21, and which is disposed parallel to the aforementioned plane E1. In the present case, the angle β is 18°.

As shown in FIG. 6, the lip 8 has a height dimension H1 that approximately corresponds to a height H2 at which a transition 31 from the step 17 to the groove flank 25 is disposed. In addition, FIG. 6 shows a bevel or a chamfer 22 on the abutting surface 28.1 that adjoins the upper groove flank 15.

FIG. 7 shows how the depression 10 is divided into two regions L1, L2 in the form of circle-sections. Region L1 has a radius R2 that corresponds to a radius R1 of the glide surface 20 and is smaller than a radius R3 of the larger region L2.

The assembled floor panels 200, 200′ are shown in FIG. 8 a. The lip 8 is accommodated within a recess 27 in the counter panel, and in a manner similar to the embodiment shown in FIG. 4, the lower projection 26 of the tongue creates a clearance 29 with the depression 10, and creates the linear contact 41 at the transition 18 from the inner wall 21 to the glide surface 20. Additionally, in a lowermost region 43 of the depression, a depression edge 42 is visible as a point. In particular, it is seen that, notwithstanding the circle-section regions L1, L2 (see FIG. 7), the depression 10 steadily rises toward the step 17.

FIG. 8 b shows solid wood floor panels 300, 300′ before and after the tongue 24 has been inserted into the groove 13. The inclined position of the floor panel 300, where the tongue 24, having a lower beveled edge 47, glides over the gently rounded step 17, is shown by a dot-dashed line. In this position, the lower projection 26 is still supported by an edge 48 formed by the upper surface 44 of the lip 8 and the glide surface 20. When the tongue 24 is pushed deeper into the groove 13, the rounded projection 26 will also glide over the glide surface 20 and sink in the direction of the depression 10 to the extent that the aforementioned clearance 29 is created there. An additional clearance 30 is, however, also created between the projection 26 and the transition 18 from the glide surface 20 to the inner wall 21. The clearance 30 has a maximum value of 0.14 mm, with a panel thickness of 14 mm.

FIG. 9 shows the aforementioned floor panel 100 or 100′ (this also applies to the floor panel 200, 200′) according to the section B-B in FIG. 1. The triple-layer floor panel 100 (100′) has a further locking mechanism 6 (left side of the figure) in the form of a trapezoidal head piece 48 that is arranged on the side face 1.2, and a groove-shaped recess 49 that adjoins the head piece 48 and is bordered by a lip 51.

As seen in FIG. 10, the head piece 48 has a trapezoidal base face 35 that runs plane-parallel to the base face 12, as well as two oblique sidewalls 36, 56 that adjoin the trapezoidal base face. The outer sidewall 36 of the head piece 48 transitions into a step 38.2 on an abutting surface 64.2. The recess 49 has a flank 65 that is oriented perpendicular to the base face 12 and is situated opposite the sidewall 56 of the head piece 48.

Accordingly, the recess 49 is shaped as an orthogonal trapezoid, the bottom 67 of which is wider than the inside width 66 of the recess 49. Additionally, in the lowermost region thereof the head piece 48 is beveled on both sides to facilitate insertion of the counter panel in a groove 34 (not depicted).

The second side face 2.2 (see right side of FIG. 9) comprises a locking mechanism 16 that is compatible with the locking mechanism 6 and bears a locking arm 33 that protrudes beyond an abutting surface 64.1 of the floor panel. The locking arm transitions into the trapezoidal lip 51 that protrudes upward.

The open groove 34 is countersunk in the locking arm 33. The groove 34 has a groove bottom 39 that is parallel to a base face 12 of the floor panel and two groove flanks 52.1, 52.2 that are inclined in such a way that the groove 34 tapers toward the top. A step 38.1 in the groove flank 52.1 adjoins the abutting surface 64.1. The groove 34 takes the form of a nearly equilateral trapezoid.

The two steps 38.1, 38.2 run parallel to the base face 12 of the floor panel and are slightly shifted with respect to each other by the fact that the height dimension of the abutting surface 64.1 slightly exceeds the height dimension of the abutting surface 64.2.

In the assembled state (see FIG. 11) a positive tongue and groove connection 50 (dovetail joint) is created, in which the groove flanks 52.1, 52.2 press against the sidewalls 36, 56 of the head piece 48. However, a clearance 37 remains between the two steps 38.1, 38.2, and a further clearance 60 remains between the trapezoid base face 35 and the groove bottom 39.

The extent of the clearance 37 as well as that of the second clearance 60 approaches a value of zero when the wood material expands.

The purpose of the two clearances 37 and 60 is to compensate for dimensional changes in the floor panels once installed. The steps 38.1, 38.2 stabilize the resulting dovetail joint 32 perpendicular to the visible face 11 and protect the abutting surfaces from destructive pressures caused by moisture-related dimensional changes in the engineered wood product. The magnitudes of the clearance 37 and the clearance 60 are negligible and, in the present case, range between 0.1 mm and 0.2 mm.

FIG. 12 shows the short side of an assembly of the solid floor panels 300, 300′. When the floor panel 300′ swings down around a swivel axis X, the head piece 48 is pressed into the groove 34 of the counter panel until a positive tongue and groove connection 50 is achieved (as in FIG. 11). The swivel axis X runs parallel to the long side of the floor panels and is defined by the cooperating parts thereof, which is to say, by the lower semicircular projection 26 of the floor panel and the glide surface 20 of the counter panel. The swivel axis X does not necessarily represent a straight line in the geometrical sense and may also be called a swivel axis region.

Examples of various features/aspects/components/operations have been provided to facilitate understanding of the disclosed embodiments of the present invention. In addition, various preferences have been discussed to facilitate understanding of the disclosed embodiments of the present invention. It is to be understood that all examples and preferences disclosed herein are intended to be non-limiting.

Although selected embodiments of the present invention have been shown and described individually, it is to be understood that at least aspects of the described embodiments may be combined.

Although selected embodiments of the present invention have been shown and described, it is to be understood the present invention is not limited to the described embodiments. Instead, it is to be appreciated that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and the equivalents thereof. 

What is claimed is:
 1. A panel-shaped, rectangular construction panel (100; 200; 300), comprising: a visible face (11); a base face (12) located opposite to the visible face (11); two first shaped side faces (1.1, 2.1) that run parallel to each other, and two other, second shaped side faces (1.2, 2.2), also parallel to each other, that run perpendicular to said side faces (1.1, 2.1), wherein all of the side faces (1.1, 2.1; 1.2, 2.2) are bordered by the visible face (11) and the base face (12); at least one pair of locking mechanisms (9, 19) that are incorporated in the side faces (1.2, 2.2) of the construction panel, are compatible with each other and, when assembled, work together to allow for a separable connection between like construction panels, wherein the locking mechanisms (9, 19) located on the side faces (1.1, 2.1) of the construction panel create a positive groove and tongue connection (40) when connected to a like construction panel, in which the locking mechanism (9) comprises a trapezoidal groove (13) that tapers in the direction of the groove bottom (14) thereof and has a first groove flank (15) that runs substantially parallel to the visible face (11), and a second, inclined groove flank (25) located opposite to the first groove flank, wherein the second groove flank (25) transitions over a rounded step (17) into a sunken depression (10) with respect to the groove (13), which is located outside of the locking mechanism (9), said depression being arranged on a side piece (4) that protrudes beyond the groove (13) and tapers into a lip (8), the lip (8) being bordered by a planar inner wall (21) and a free surface (44) that is plane-parallel to the base face (12), and in which the locking mechanism (19) also comprises a trapezoidal tongue (24) that engages in the groove (13) and additionally transitions into an approximately semicircular projection (26) that is oriented toward the base face (12) and will be accommodated in the depression (10), wherein the semicircular projection (26) adjoins a recess (27) in which the lip (8) engages; characterized in that: the inner wall (21) of the lip (8) extends, on one hand, to a rounded glide surface (20) facing a depression (10) and adjoining the free surface (44) of the lip (8) and, on the other hand, to a depression edge (42) located in a lowermost region (43) of the depression (10) near the base face (12), so that the depression (10), starting from the depression edge (42) thereof, rises steadily toward the rounded step (17); and after the tongue (24) has been inserted into the groove (13), the projection (26) is accommodated in the depression (10) in such a way that a clearance (30) approaching a zero value is created between the projection (26) and a transition (18) from the inner wall (21) to the glide surface (20), or a linear contact (41) is formed.
 2. A construction panel according to claim 1, characterized in that the inner wall (21) is arranged perpendicularly or obliquely with respect to the base face (12).
 3. A construction panel according to claim 1, characterized in that the step (17) is located between the depression (10) and a plane (E1) that runs perpendicular to the visible face (11), and is defined as a continuation of an abutting surface (28.1) of the construction panel.
 4. A construction panel according to claim 1, characterized in that the inner wall (21) is arranged at an acute angle (β) with respect to a plane (E2) that is defined by the transition (18) from the glide surface (20) to the inner wall (21) and is parallel with respect to said plane (E1).
 5. A construction panel according to claim 4, characterized in that the angle (β) is between 1° and 45°, but preferably between 16° and 20°, with particular preference being placed on an angular value of 18° with an angular tolerance of ±0.5°.
 6. A construction panel according to claim 1, characterized in that the clearance (30) has a value between 0.01 mm and 0.20 mm.
 7. A construction panel according to claim 6, characterized in that the clearance (30) is a maximum 0.14 mm.
 8. A construction panel according to claim 1, characterized in that the linear contact (41) occurs at the transition (18).
 9. A construction panel according to claim 1, characterized in that the lip (8) has a height dimension (H1) that approximately corresponds to a height (H2) where a transition (31) from the step (17) to the groove flank (25) is located.
 10. A construction panel according to claim 1, characterized in that the depression (10) is divided into two circle-section regions (L1, L2), the region (L1) of which has a radius (R2) that equals a radius (R1) of the glide surface (20).
 11. A construction panel according to claim 10, characterized in that the region (L2) of the depression (10) has a radius (R3) that exceeds the value of the radius (R2).
 12. A construction panel according to claim 1, characterized in that the construction panel is solid.
 13. A construction panel according to claim 1, characterized in that the construction panel has multiple layers.
 14. A construction panel according to claim 1, characterized in that the construction panel is a wall, ceiling, or floor panel.
 15. A construction panel according to claim 1, characterized in that the construction panel is a furniture panel.
 16. A surface covering comprising assembled construction panels according to claim
 1. 